cDAQ

[oliver_C]

Hi

We are using a cDAQ 9172 Chassis containing a NI 9237 Bridge module and an NI 9401 TTL I/0 module configured with SignalExpress 2.5. We would like to sample the analog output of a sensor whose signal varies with the rotational angle of our hardware. We also have a TTL signal from an angle encoder on the hardware which outputs a square wave signal whose period varies with the rotational velocity which is not constant. We can set the encoder to give 1 TTL cycle per degree of rotation.

We want to input our sensor signal to the Bridge module and sample it on every rising edge of the TTL signal, which is input to the 9401.

The fastest rotational rate we are interested in corresponds to a TTL signal period of about 20 microsec so the analog sampling process must be fast enough to permit sampling at about 50kHz.

We would be very grateful for a simple, non-specialist level explanation of how to do this using the SignalExpress software.

[Johann.Wagner]

Dear trafag,

 for using a trigger task in Signal Express, MAX Task or Labview you need additionally a trigger module (e.g. 9205 in slot 5 or 6 pf cdaq 9172). Then you have the PFI0 Line available in your analog input task with digital triggering for example. See following link for explanation and my screenshots i attached here.

http://digital.ni.com/public.nsf/allkb/4859504F14AF68DB8625721100640F26?OpenDocument

So now you can give your Signal to the 9205 module for Triggering and can acquire your datas on your 9237 module with 50 kHz... Only with 9401

Best Regards

Johann

[Johann.Wagner]

Also when putting your 9401 module in slot 5 and your 9237 module in slot 1, make an DMS Task and set trigger - you see all you PFI lines of the 9401. So fortunatelly you need no additionally module